There has been considerable interest in recent years in non-aqueous batteries. An attractive feature of these batteries is their potentially high voltage and high energy densities. Particularly attractive are non-aqueous batteries using lithium negative electrodes since lithium has high standard potential and low density, so that such electrodes can have exceptionally high energy densities (see for example, High Energy Batteries by R. Janinski, Plenum Press, New York, 1967, pp. 140-144). Similar statements can be made for other Group I and Group II elements such as sodium, potassium and magnesium.
Exceptionally good active materials for the positive electrode of lithium non-aqueous batteries are niobium chalcogenides such as niobium triselenide and niobium trisulfide (see for example, U.S. Pat. No. 3,864,167 issued on Feb. 4, 1975 to J. Broadhead et al, incorporated herein by reference). These electrode materials not only have high energy density, good charge and discharge characteristics (cycle performance) and good stability, but also are relatively available and compatible with a large variety of electrolyte systems. Tests carried out on lithium cells made with these positive electrode materials (especially with niobium triselenide) confirm the advantages outlined above.
Electrodes comprising NbSe.sub.3 can be fabricated by providing a thin Nb foil and reacting it with Se vapor. The resulting fibrous sheet of NbSe.sub.3 is then rolled onto a metal grid that serves as current collector. NbS.sub.3 containing electrodes can be similarly produced. The above process has several shortcomings, including relatively high materials cost, and relatively long reaction time. Furthermore, it is generally difficult to produce thin sheets of active material of uniform thickness by means of the prior art technique.
In order to increase the commercial value of using chalcogenides such as NbSe.sub.3 as the active positive electrode material in non-aqueous cells, it is desirable to reduce the cost of fabricating cells with chalcogenide active material and to make the fabrication procedure more easily adaptable to mass production. In particular, it is desirable to find a synthesis procedure for NbSe.sub.3 (and NbS.sub.3) active electrode material that is less expensive, that can be used to produce thin sheets of active material of uniform thickness, and that is less cumbersome and/or more easily adapted to mass production under manufacturing conditions than those known to the prior art. This application discloses such a procedure.